To address the issue whether infected DC process pathogen-derived antigen and stimulate antigen-specific CD4+ T cells in vivo, we have infected susceptible BALB/c (H2-d) mice with a recombinant Leishmania major parasite expressing a fluorescent tracer. We have directly visualized antigen-presenting cells using a mAb reacting to an antigenic peptide derived from the parasite LACK antigen bound to I-Ad MHC class II molecule. I-Ad/LACK complexes were readily detected at the surface of freshly purified parasite-containing DC which expressed a CD8?- CD11b+ F4/80+ g...

These mice were immunized with LACK and used in a DC staining experiment. LN cells were purified 2 days later, and stained with either 2C44, 2F74, 2E60 or 2X8 mAb. None of these mAb stained DC purified from non immunized mice. Among the 4 mAb, only 2C44 could stain DC in LACK-immunized mice, but not in OVA-immunized mice.

These mice were used for transcriptional profiling of macrophages stimulated with different stimuli at different time points in the presence or absence of a kinase inhibitors.